The present invention relates to a communication network and in particular to charge allocation in multi-user networks in which access to the network is not controlled by the network provider.
With the advent of multi-user computer networks, whereby users can communicate with one another via user access points such as terminals included in the network across a communication medium such as telephone lines, the problem of how the users may be charged by the network provider for using a network has arisen.
When a particular network is used by a single customer only (e.g. private circuits), then the network provider can determine the total cost of providing that network and use this information to set the charges for the customer. However, where a network is used by more than one customer, the network provider must apportion the network charges in some way.
Where the network has some means of controlling customer access (access control) to the network then this same mechanism can also be used to monitor, and hence charge for, customers' usage of the network. A network incorporating access control means is shown schematically in FIG. 1. Users access the network designated generally as 1 via one of a plurality of terminals 2 all of which are connected to the network backbone 3. Each terminal 2 accesses the network backbone 3 via a respective access control 4. In the example shown the access control 4 is terminal-specific and can be arranged to record charging data such as call length, call type and/or call duration and ensure that the charge is attributed to the associated terminal 2.
For many network types, however, the network provider does not have a means of controlling customer access such as that described above. Whilst the network provider in such cases could place an access control mechanism such as a usage monitor at each point of connection into the network, the provision, security, maintenance, and monitoring (to collect charge records) of such usage monitors would give rise to considerable expense and operational difficulties.
In fact such arrangements will gave rise to considerable problems. This is a particularly significant point when it is recognized that many of the network types which do not provide an access control mechanism are the most commonly used network types such as:
Local, wide and metropolitan area networks (LANs, WANs & MANs) e.g. office ethernet LANs. PA1 The ether, for example user to user direct radio communication. PA1 The proposed optical ether.
One solution is for network providers to charge their customers some form of subscription. Charging by subscription, though, may discourage potential customers who only expect to make limited use of the network and who would therefore effectively end up subsidising customers who are high network users.
Alternatively, where the network is provided as part of a package together with one or more value-added services, the service provider may incorporate the network costs into the value-added service charges to the end customers. In this case, however, the network is effectively being supplied to the service provider by an internal network provider; with the service provider paying the entire network cost. This is then a single-user rather than multi-user scenario.
One of the essential characteristics of a broadcast network such as the examples listed earlier, is that the network traffic must traverse every potential access point in the network. Thus the entirety of the network traffic may be monitored at a single point, or, optionally in the case of dispersive media such as the ether (air) at a number of points throughout the network domain. In either case the number of monitoring points can be small in number compared to the number of customers using the network and the monitoring points can be removed from the customers' points of entry into the network. Such a system is shown in FIG. 2. Once again network 1 includes a plurality of. terminals 2 and a network backbone 3. In this case, however, there are no access controls 4 but instead a single monitoring point 5 is provided on the network backbone 3 through which all traffic passes.
U.S. Pat. No. 5,406,555 assigned to NEC Corporation relates to a local area network in which a charging apparatus is used in the local area network (LAN) or in bridge apparatus interconnecting the LANs. Packets passing though the charging apparatus include source and destination addresses, and packet counts are accumulated against the various combinations of source and destination addresses. Usage charges can be raised accordingly.
A problem associated with that system is that, in many cases, a call initiated by one customer to another may result in traffic flows back and forth between both parties for the duration of their interaction. Under the scheme described in U.S. Pat. No. 5,406,555 there is no means of determining how the individual packets comprising such interactive calls should be charged. For example a packet with customer A as the source and customer B as the destination could be part of an interaction sequence chargeable to A or B; there is no way to tell.
A solution proposed in JP 63290042 of NEC Engineering Corporation is to introduce an extra field, in addition to the source and destination identifiers (addresses), which would identify who should be charged; source, destination, or some third party. The problem with introducing an extra field is that in most cases it would not be compatible with the existing protocols already in widespread use.